3.1.3.12
Expansion Control
Provide bends, loops, and offsets wherever practical to relieve
overstressed piping systems due to thermal expansion and to provide
adequate flexibility. Cold spring piping system as indicated but not more
than an amount greater than 50 percent of the total linear expansion.
3.1.3.13
Connection to Equipment
Provide unions or flanges where necessary to permit easy disconnection of
piping and apparatus. Provide unions and gate valves at each connection to
threaded end control valves, strainers and equipment.
3.1.3.14
Valve Installation
Install valves in positions accessible for operation and repair. Install
stems in a vertical position with handwheels or operators on top or in a
horizontal position. Do not install handwheels on stop valves below the
valve. When the centerline of any valve is more than 2 meters 7 feet above
the floor or platform, provide the valve with a chain-operated handwheel.
When the valve is motorized, provide hand operation for emergency use.
a.
Gate Valves: Arrange back outlet gate valves for turbine exhaust
for hand operation and provide with a floor stand.
b.
Globe Valves: Pressure shall be below the disc. Install globe
valves with stems horizontal on steam and exhaust lines, when
better drainage is required or desired.
c.
Steam Pressure-Reducing Valves: Provide the steam line entering
each pressure-reducing valve with a strainer. Provide each
pressure-reducing valve unit with two shutoff valves and with a
globe or angle bypass valve and bypass pipe. A bypass around a
reducing valve shall be of reduced size to restrict its capacity
to approximately that of the reducing valve. Provide each
pressure-reducing valve unit with indicating steam gages to show
the reduced pressure and the upstream pressure and an adequately
sized safety valve on the low pressure side.
d.
Valve Tags and Charts: Permanently tag each valve with a black
and white engraved laminated plastic tag showing valve number,
valve function and piping system and whether another valve must be
opened or closed in conjunction with this valve. Provide a typed
chart which will show the required valve tagging plus the location
of each valve; frame valve charts under glass and install as
directed.
3.1.3.15
Traps and Connections
Traps shall be of the type and capacity for the service required, and shall
be properly supported and connected. Except for thermostatic traps in pipe
coils, radiators, and convectors, install traps with a dirt pocket and
strainer between it and the piping or apparatus it drains. Whenever it is
necessary to maintain in continuous service apparatus or piping which is to
be drained, provide a three valve bypass so that the trap may be removed
and repaired and condensate drained through the throttled bypass valve.
Provide a check valve on the discharge side of the trap whenever the trap
is installed for lift or operating against a back pressure, or it
discharges into a common return line. Provide test connections on the
SECTION 15502N
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